Portable energy storage device and portable energy storage system

Abstract

The utility model discloses a power-up pack device for a portable energy storage device. The power-up pack device comprises a battery pack, an online capacity expansion module and a sampling control module, the battery pack is connected with a direct current bus through the online capacity expansion module, and the direct current bus is connected with a bidirectional DC / AC converter of the portable energy storage device; the sampling control module comprises a first voltage sampling circuit, a second voltage sampling circuit and a control circuit; the first voltage sampling circuit is used for detecting the voltage of a direct-current bus, the second voltage sampling circuit is used for detecting the voltage of a battery pack, and the control circuit is used for controlling the online capacity expansion module to connect the battery pack to the direct-current bus online based on the voltage of the direct-current bus, the voltage of the battery pack and a parallel operation threshold value. According to the utility model, the battery pack can be instantly and online added to the DC bus, so that online capacity expansion of the battery pack without shutdown is realized, and the whole circuit is simple in structure, low in cost and low in power consumption, thereby being suitable for a portable energy storage device.

Description

Technical Field

[0001] The utility model relates to the field of energy storage devices, and more specifically, to a power pack device for a portable energy storage device, and a portable energy storage system comprising the power pack device. Background Art

[0002] Small portable energy storage devices have gradually become an important backup in daily life. They can be widely used in daily camping, home backup power, and villas or high-end residential areas. Existing energy storage devices can support the expansion of suitable power packs to achieve the purpose of doubling capacity to meet the power problems in certain emergency situations.

[0003] A large-capacity battery energy storage bidirectional converter is disclosed in the Chinese invention patent application publication document CN102122826A, in which each battery branch collects DC energy to the DC bus through a DC / DC converter, and then connects to the AC power grid or operates independently with load through a subsequent DC / AC converter. However, this design requires a two-stage (DC / DC+DC / AC) multi-group access structure, so there are technical problems of high cost and high power consumption. It is more oriented towards energy storage power station systems and cannot be applied to portable energy storage devices. Other existing small portable energy storage devices usually need to be shut down as a whole before connecting when adding a battery pack. Utility Model Content

[0004] The technical problem to be solved by the present invention is to provide a power-up pack device which has a simple circuit structure, low cost, low power consumption, and can achieve online battery pack capacity expansion without stopping, suitable for a portable energy storage device, and a portable energy storage system including the power-up pack device, in view of the above-mentioned defects of the prior art.

[0005] The technical solution adopted by the utility model to solve the technical problem is: constructing a power pack device for a portable energy storage device, including a battery pack, an online expansion module and a sampling control module;

[0006] The battery pack is connected to a DC bus through the online expansion module, and the DC bus is connected to a bidirectional DC / AC converter of the portable energy storage device;

[0007] The sampling control module includes a first voltage sampling circuit, a second voltage sampling circuit and a control circuit; the first voltage sampling circuit is used to detect the DC bus voltage, the second voltage sampling circuit is used to detect the battery pack voltage, and the control circuit is used to control the online expansion module to connect the battery pack online to the DC bus based on the DC bus voltage, the battery pack voltage and the parallel threshold.

[0008] In the power pack device for a portable energy storage device described in the utility model, the online expansion module includes a first contactor, a second contactor and an anti-reverse diode, the first end of the first contactor is connected to the positive electrode of the battery pack, and the second end is connected to the positive DC bus, the first end of the second contactor is connected to the positive electrode of the battery pack, and the second end is connected to the anode of the anti-reverse diode, the cathode of the anti-reverse diode is connected to the positive DC bus, and the negative electrode of the battery pack is connected to the negative DC bus;

[0009] The control circuit is used to control the first contactor to close and the second contactor to open, or control the second contactor to close and the first contactor to open based on the DC bus voltage, the battery pack voltage and the parallel threshold.

[0010] In the power pack device for portable energy storage device described in the utility model, the sampling control module further includes a device-incorporated judgment circuit, and the device-incorporated judgment circuit is used to obtain the battery pack status;

[0011] The control circuit is further configured to maintain current states of the first contactor and the second contactor based on the battery pack state, or control the first contactor and the second contactor to be disconnected.

[0012] In the power pack device for a portable energy storage device described in the utility model, the first voltage sampling circuit includes a differential sampling unit, a voltage following unit, a filtering unit and a voltage protection unit, the input end of the differential sampling unit is connected to the positive DC bus and the negative DC bus, and the output end is connected to the first input end of the control circuit via the voltage following unit, the filtering unit and the voltage protection unit in sequence.

[0013] In the power pack device for a portable energy storage device described in the utility model, the second voltage sampling circuit includes a differential sampling unit, a voltage following unit, a filtering unit and a voltage protection unit, the input end of the differential sampling unit is connected to the positive and negative poles of the battery pack, and the output end is connected to the second input end of the control circuit via the voltage following unit, the filtering unit and the voltage protection unit in sequence.

[0014] Another technical solution adopted by the utility model to solve its technical problem is to construct a portable energy storage system, including a portable energy storage device and at least one power pack device;

[0015] The power pack device includes a battery pack, an online expansion module and a sampling control module; the battery pack is connected to a DC bus through the online expansion module, and the DC bus is connected to a bidirectional DC / AC converter of the portable energy storage device;

[0016] The sampling control module includes a first voltage sampling circuit, a second voltage sampling circuit and a control circuit; the first voltage sampling circuit is used to detect the DC bus voltage, the second voltage sampling circuit is used to detect the battery pack voltage, and the control circuit is used to control the online expansion module to connect the battery pack online to the DC bus based on the DC bus voltage, the battery pack voltage and the parallel threshold;

[0017] The online expansion module includes a first contactor, a second contactor and an anti-reverse diode, wherein the first end of the first contactor is connected to the positive electrode of the battery pack, and the second end is connected to the positive DC bus, the first end of the second contactor is connected to the positive electrode of the battery pack, and the second end is connected to the anode of the anti-reverse diode, the cathode of the anti-reverse diode is connected to the positive DC bus, and the negative electrode of the battery pack is connected to the negative DC bus;

[0018] The control circuit is used to control the first contactor to close and the second contactor to open, or control the second contactor to close and the first contactor to open based on the DC bus voltage, the battery pack voltage and the parallel threshold.

[0019] In the portable energy storage system described in the utility model, the sampling control module further includes a device incorporation judgment circuit, and the device incorporation judgment circuit is used to obtain the battery pack status;

[0020] The control circuit is further configured to maintain current states of the first contactor and the second contactor based on the battery pack state, or control the first contactor and the second contactor to be disconnected.

[0021] In the portable energy storage system described in the utility model, the first voltage sampling circuit includes a differential sampling unit, a voltage following unit, a filtering unit and a voltage protection unit. The input end of the differential sampling unit is connected to the positive DC bus and the negative DC bus, and the output end is connected to the first input end of the control circuit via the voltage following unit, the filtering unit and the voltage protection unit in sequence.

[0022] In the portable energy storage system described in the utility model, the second voltage sampling circuit includes a differential sampling unit, a voltage following unit, a filtering unit and a voltage protection unit. The input end of the differential sampling unit is connected to the positive and negative poles of the battery pack, and the output end is connected to the second input end of the control circuit via the voltage following unit, the filtering unit and the voltage protection unit in sequence.

[0023] The portable energy storage system described in the utility model comprises a plurality of power pack devices, each of which is respectively connected to the DC bus.

[0024] To implement the utility model, the battery pack can be added to the DC bus instantly and online only by simply using the sampling control module to control the conduction and disconnection of the line expansion module, thereby realizing online battery pack capacity expansion without stopping the machine. In addition, the entire circuit structure is simple, the cost is low, and the power consumption is low, so it is suitable for portable energy storage devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0026] Figure 1 It is a principle block diagram of a preferred embodiment of a power pack device of a portable energy storage device of the utility model;

[0027] Figure 2 It is a circuit schematic diagram of a preferred embodiment of a power pack device for a portable energy storage device of the utility model;

[0028] Figure 3 It is a circuit schematic diagram of a voltage sampling circuit 1 of a power pack device for a portable energy storage device of the utility model;

[0029] Figure 4 It is a circuit schematic diagram of a voltage sampling circuit 2 of a power pack device for a portable energy storage device of the utility model;

[0030] Figure 5 It is a principle block diagram of a preferred embodiment of the portable energy storage system of the utility model. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0032] Figure 1 1 is a principle block diagram of a preferred embodiment of a power pack device for a portable energy storage device of the utility model. Figure 1As shown, the power pack device 100 for the portable energy storage device 200 includes a battery pack 110, an online expansion module 120 and a sampling control module 130. The battery pack 110 is connected to the DC bus through the online expansion module 120, and the DC bus is connected to the bidirectional DC / AC converter 210 of the portable energy storage device 200. The sampling control module 130 includes a voltage sampling circuit 2, a voltage sampling circuit 1 and a control circuit 133. The voltage sampling circuit 2 is used to detect the DC bus voltage, the voltage sampling circuit 1 is used to detect the battery pack voltage, and the control circuit 133 is used to control the online expansion module 120 to connect the battery pack 110 online to the DC bus based on the DC bus voltage, the battery pack voltage and the parallel threshold.

[0033] like Figure 1 As shown, the DC bus includes a positive DC bus DC+ and a negative DC bus DC-, and the positive electrode BAT+ and the negative electrode BAT- of the battery pack 110 are respectively connected to the input end of the online expansion module 120. The output end of the online expansion module 120 is respectively connected to the positive DC bus DC+ and the negative DC bus DC-. When the online expansion module 120 is turned on, the battery pack 110 is connected to the DC bus online, and when the online expansion module 120 is disconnected, the battery pack 110 is disconnected from the DC bus.

[0034] The control circuit 133 is used to control the online expansion module 120 to connect the battery pack 110 online to the DC bus based on the DC bus voltage, the battery pack voltage and the parallel threshold. Specifically, in a preferred embodiment of the present utility model, the voltage sampling circuit 2 is connected between the positive DC bus DC+ and the negative DC bus DC- to detect the DC bus voltage, and the voltage sampling circuit 1 is connected between the positive electrode BAT+ and the negative electrode BAT- of the battery pack 110 to detect the battery pack voltage. The voltage sampling circuit 2 and the voltage sampling circuit 1 can be constructed using any known voltage sampling device, such as a voltmeter, a sampling resistor, etc., which all fall within the protection scope of the present utility model.

[0035] The control circuit 133 is used to receive the DC bus voltage and the battery pack voltage, and obtain the difference therebetween, and then compare the difference with the built-in or received parallel threshold. When the difference is less than or equal to the parallel threshold, the control circuit 133 controls the online expansion module 120 to turn on, and the battery pack 110 is now connected online to the DC bus. Here, the parallel threshold is the minimum voltage difference for the battery pack to be connected in parallel, provided by the battery pack manufacturer. Here, the battery pack 110 can use any suitable product sold on the market, and the parallel threshold can be obtained according to its instruction manual.

[0036] When the difference is greater than the parallel threshold, the control circuit 133 controls the online expansion module 120 to disconnect, and the battery pack 110 cannot be connected to the DC bus. This control process is not only applicable to the case where the battery pack 110 is added to the portable energy storage device to expand the battery capacity, but also to the case where the battery pack needs to be recharged. Because the DC bus is connected to the bidirectional DC / AC converter 210 of the portable energy storage device 200, after the battery pack 110 is connected to the DC bus, the bidirectional DC / AC converter 210 can be used to supply power to the load, and the bidirectional DC / AC converter 210 can also be used to receive electrical energy, thereby charging the battery pack 110.

[0037] In a preferred embodiment of the present utility model, the control circuit 133 may include a differential circuit and a comparator to realize the difference acquisition and comparison functions. Of course, in other preferred embodiments of the present utility model, a differential voltage detection chip may also be used to realize the functions of the voltage sampling circuit 2, the voltage sampling circuit 1 and the control circuit 133, which all fall within the protection scope of the present utility model. In a preferred embodiment of the present utility model, the online expansion module 120 may use any suitable switching device, such as a contactor, a contactor, etc., as long as it can be a controlled switch.

[0038] The implementation of the power pack device 100 for a portable energy storage device of the utility model only requires the simple use of the sampling control module 130 to control the conduction and disconnection of the line expansion module 120 to instantly and online add the battery pack 110 to the DC bus, thereby achieving online battery pack capacity expansion without stopping the machine. Moreover, the entire circuit does not need to adopt a two-stage type (DC / DC+DC / AC) as in the prior art, so it has a simple structure, low cost, and low power consumption, and is therefore suitable for portable energy storage devices.

[0039] Figure 2 1 is a circuit diagram of a preferred embodiment of a power pack device for a portable energy storage device of the utility model. Figure 2As shown, the power pack device 100 for the portable energy storage device 200 includes a battery pack 110, an online expansion module 120 and a sampling control module 130. The battery pack 110 is connected to the DC bus through the online expansion module 120, and the DC bus is connected to the bidirectional DC / AC converter 210 of the portable energy storage device 200. The sampling control module 130 includes a voltage sampling circuit 1, a voltage sampling circuit 2 and a control circuit 133. The voltage sampling circuit 2 is connected between the positive DC bus DC+ and the negative DC bus DC- to detect the DC bus voltage, and the voltage sampling circuit 1 is connected between the positive electrode BAT+ and the negative electrode BAT- of the battery pack 110 to detect the battery pack voltage. The control circuit 133 is used to control the online expansion module 120 to connect the battery pack 110 online to the DC bus based on the DC bus voltage, the battery pack voltage and the parallel threshold.

[0040] exist Figure 2 In the preferred embodiment shown, the online expansion module 120 includes a contactor KM1, a contactor KM2 and an anti-reverse diode D1. Figure 2 As shown, the first end of the contactor KM1 is connected to the positive electrode BAT+ of the battery pack 110, and the second end is connected to the positive DC bus DC+. The first end of the contactor KM2 is connected to the positive electrode BAT+ of the battery pack 110, and the second end is connected to the anode of the anti-reverse diode D1. The cathode of the anti-reverse diode D1 is connected to the positive DC bus DC+, and the negative electrode of the battery pack 110 is connected to the negative DC bus DC-. The control circuit 133 is used to control the contactor KM1 to close and the contactor KM2 to open, or to control the contactor KM2 to close and the contactor KM1 to open, based on the DC bus voltage, the battery pack voltage, and the parallel threshold. In this preferred embodiment, the online expansion module 120 is constructed using contactors KM1, KM2, and anti-reverse diodes, which not only has a simple circuit and low cost, but also facilitates the subsequent use of a simple control circuit to control it.

[0041] In this preferred embodiment, the same voltage sampling circuit is preferably used to implement the sampling of the DC bus voltage and the battery pack voltage. That is, preferably, the voltage sampling circuit 1 includes a differential sampling unit, a voltage following unit, a filtering unit and a voltage protection unit, the input end of the differential sampling unit is connected to the positive and negative poles of the battery pack, and the output end is connected to the first input end of the control circuit via the voltage following unit, the filtering unit and the voltage protection unit in sequence. Similarly, the voltage sampling circuit 2 also includes a differential sampling unit, a voltage following unit, a filtering unit and a voltage protection unit, the input end of the differential sampling unit is connected to the positive DC bus DC+ and the negative DC bus DC-, and the output end is connected to the second input end of the control circuit 133 via the voltage following unit, the filtering unit and the voltage protection unit in sequence.

[0042] In this preferred embodiment, the control circuit 133 includes an MCU and a contactor switch circuit. The MCU is used to receive the DC bus voltage and the battery pack voltage, and obtain the difference, and then compare the difference with the built-in or received parallel threshold. When the difference is less than or equal to the parallel threshold, a first control signal is output, and when the difference is greater than the parallel threshold, a second control signal is output. When the contactor control circuit receives the first control signal, the contactor KM1 is controlled to be closed and the contactor KM2 is disconnected. When the contactor control circuit receives the second control signal, the contactor KM2 is controlled to be closed and the contactor KM1 is disconnected. The use of MCU and contactor switch circuit is not only low-cost, but also uses conventional low-cost devices in the field, so it is easy to implement. Here, the MUC can use a common MCU chip in the field, and the contactor switch circuit can select a corresponding control chip according to the specific contactor used. Those skilled in the art can achieve this selection based on the teachings of the utility model and common knowledge in the field.

[0043] The principle is described in detail below: The battery pack 110 is connected to the DC bus through the online expansion module 120, and the DC bus is connected to the power grid through a bidirectional DC / AC converter or independently connected to a load for operation.

[0044] Specifically, when a battery pack 110 needs to be added, the voltage sampling circuit 2 is used to detect the DC bus voltage, and the voltage sampling circuit 1 is used to detect the battery pack voltage, and the detected DC bus voltage is returned to the MCU. The MCU obtains the difference between the two and compares the difference with the built-in parallel threshold. Here, it is common knowledge in the art to use the MCU to obtain the voltage difference and compare it with the threshold, and this function can be achieved by purchasing an MCU with a built-in program. When the difference is less than or equal to the parallel threshold, the MCU outputs a first control signal, and when the difference is greater than the parallel threshold, the MCU outputs a second control signal. When the contactor control circuit receives the first control signal, the contactor KM1 is controlled to be closed and the contactor KM2 is disconnected. When the contactor control circuit receives the second control signal, the contactor KM2 is controlled to be closed and the contactor KM1 is disconnected. When the contactor KM2 is closed and the contactor KM1 is disconnected, due to the presence of the anti-reverse diode D1, the circuit will not be turned on, so the battery pack 100 will not be connected to the circuit. When the contactor KM1 is closed and KM2 is disconnected, the battery pack 100 can be connected to the DC bus, thereby being connected online to the system to expand the battery capacity.

[0045] When the battery pack 110 needs to be recharged, the bidirectional DC / AC converter 200 recharges the battery pack 110. At this time, if the state of the contactor at this time is that the contactor KM1 is closed and the contactor KM2 is disconnected, that is, the battery pack 110 is already connected to the DC bus, and it directly obtains the charging voltage from the DC bus for recharging. If the state of the contactor at this time is that the contactor KM2 is closed and the contactor KM1 is disconnected, then the aforementioned steps are also performed, that is, the voltage sampling circuit 2 is used to detect the DC bus voltage, and the voltage sampling circuit 1 is used to detect the battery pack voltage, and the detected DC bus voltage and battery pack voltage are returned to the MCU. The MCU calculates the difference between the two and compares the difference with the built-in parallel threshold. When the difference is less than or equal to the parallel threshold, the MCU outputs a first control signal, and when the difference is greater than the parallel threshold, the MCU outputs a second control signal. When the contactor control circuit receives the first control signal, it controls the contactor KM1 to close and the contactor KM2 to open. At this time, the battery pack 110 can obtain charging voltage from the DC bus to supplement power.

[0046] exist Figure 2 In the preferred embodiment shown, the sampling control module 130 further includes a device incorporating a judgment circuit, and the device incorporating a judgment circuit is used to obtain the battery pack state. The control circuit 133 is further used to maintain the current state of the contactor KM1 and the contactor KM2 based on the battery pack state, or control the contactor KM1 and the contactor KM2 to be disconnected.

[0047] Specifically, in this preferred embodiment, in this preferred embodiment, the control circuit 133 includes an MCU and a contactor switch circuit. The MCU is used to receive the battery pack state state. The device incorporation judgment circuit can directly communicate with the battery pack 100, thereby obtaining the battery pack state state to determine whether the battery pack 100 is incorporated into the system (i.e., whether it is connected to the DC bus). If the battery pack state state is when the battery pack is continuously connected, a maintenance signal is sent to the contactor switch circuit, and when the contactor switch circuit receives the maintenance signal, the current state of contactor KM1 and contactor KM2 is maintained. If the battery pack state state is when the battery pack is disconnected, a disconnection signal is sent to the contactor switch circuit, and when the contactor switch circuit receives the disconnection signal, contactor KM1 and contactor KM2 are disconnected. Thereafter, the battery pack 110, the online expansion module 120, and the sampling control module 130 are restored to their original state, waiting to be put into use next time.

[0048] In a further preferred embodiment of the utility model, after the battery pack 110 in one power pack device 100 is consumed to a large extent, another power pack device 100 can be directly put into use without removing the previous power pack device 100, thereby realizing online parallel expansion of multi-stage power pack devices.

[0049] Figure 3 It is a circuit schematic diagram of a voltage sampling circuit 1 of a power pack device for a portable energy storage device of the utility model. Figure 4 It is a circuit schematic diagram of a voltage sampling circuit 2 of a power pack device for a portable energy storage device of the utility model.

[0050] When the control circuit 133 includes an MCU and a contactor switch circuit, the voltage sampling circuit 1 includes a differential sampling unit, a voltage following unit, a filter unit, and an ADC port voltage protection unit, the input end of the differential sampling unit is connected to the positive electrode BAT+ and the negative electrode of the battery pack 110, and the output end is connected to the ADC port of the MCU through the voltage following unit, the filter unit, and the ADC port voltage protection unit in sequence. The voltage sampling circuit 2 includes a differential sampling unit, a voltage following unit, a filter unit, and a voltage protection unit, the input end of the differential sampling unit is connected to the positive DC bus DC+ and the negative DC bus DC-, and the output end is connected to the ADC port of the MCU through the voltage following unit, the filter unit, and the ADC port voltage protection unit in sequence. The voltage sampling circuit 1 and the voltage sampling circuit 2 can be connected to the ADC port of the same or different MCUs. Here, the aforementioned differential sampling unit, voltage following unit, filter unit, and ADC port voltage protection unit can be constructed using any circuit, unit, chip, or module known in the art. Of course, as mentioned above, the voltage sampling circuit 1 and the voltage sampling circuit 2 may also select different sampling circuits, or may adopt any other suitable voltage sampling devices, all of which fall within the protection scope of the present utility model.

[0051] The implementation of the power pack device for a portable energy storage device of the utility model only requires the simple use of a sampling control module to control the conduction and disconnection of the line expansion module so that the battery pack can be added to the DC bus instantly and online, thereby achieving online battery pack capacity expansion without stopping the machine. In addition, the entire circuit structure is simple, the cost is low, and the power consumption is low, so it is suitable for portable energy storage devices.

[0052] Figure 5 : is a principle block diagram of a preferred embodiment of the portable energy storage system of the utility model. Figure 5 As shown, the portable energy storage system includes a portable energy storage device 200 and three power pack devices 100. Of course, in other preferred embodiments of the present invention, other numbers of power pack devices may be used, such as one, two, four or other numbers, which all fall within the protection scope of the present invention. Here, the portable energy storage device 200 may adopt any known portable energy storage device structure in the art, and the power pack device 100 may refer to Figure 1-4 Each of the power pack devices 100 is connected to the DC bus, and its working principle and beneficial effect diagram can be referred to. Figure 1-4 Any embodiments in the above will not be described again here.

[0053] Although the present invention is described through specific embodiments, it should be understood by those skilled in the art that various changes and equivalent substitutions may be made to the present invention without departing from the scope of the present invention. In addition, various modifications may be made to the present invention for specific situations or materials without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but should include all implementation methods that fall within the scope of the claims of the present invention.

[0054] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A power pack device for a portable energy storage device, characterized in that: Including battery pack, online expansion module and sampling control module; The battery pack is connected to a DC bus through the online expansion module, and the DC bus is connected to a bidirectional DC / AC converter of the portable energy storage device; The sampling control module includes a first voltage sampling circuit, a second voltage sampling circuit and a control circuit; the first voltage sampling circuit is used to detect the DC bus voltage, the second voltage sampling circuit is used to detect the battery pack voltage, and the control circuit is used to control the online expansion module to connect the battery pack online to the DC bus based on the DC bus voltage, the battery pack voltage and the parallel threshold.

2. The power pack device for a portable energy storage device according to claim 1, characterized in that: The online expansion module includes a first contactor, a second contactor and an anti-reverse diode, wherein the first end of the first contactor is connected to the positive electrode of the battery pack, and the second end is connected to the positive DC bus, the first end of the second contactor is connected to the positive electrode of the battery pack, and the second end is connected to the anode of the anti-reverse diode, the cathode of the anti-reverse diode is connected to the positive DC bus, and the negative electrode of the battery pack is connected to the negative DC bus; The control circuit is used to control the first contactor to close and the second contactor to open, or control the second contactor to close and the first contactor to open based on the DC bus voltage, the battery pack voltage and the parallel threshold.

3. The power pack device for a portable energy storage device according to claim 2, characterized in that: The sampling control module further includes a device incorporation judgment circuit, and the device incorporation judgment circuit is used to obtain the battery pack status; The control circuit is further configured to maintain current states of the first contactor and the second contactor based on the battery pack state, or control the first contactor and the second contactor to be disconnected.

4. The power pack device for a portable energy storage device according to claim 2, characterized in that: The first voltage sampling circuit includes a differential sampling unit, a voltage following unit, a filtering unit and a voltage protection unit. The input end of the differential sampling unit is connected to the positive DC bus and the negative DC bus, and the output end is connected to the first input end of the control circuit via the voltage following unit, the filtering unit and the voltage protection unit in sequence.

5. The power pack device for a portable energy storage device according to claim 2, characterized in that: The second voltage sampling circuit includes a differential sampling unit, a voltage following unit, a filtering unit and a voltage protection unit. The input end of the differential sampling unit is connected to the positive and negative poles of the battery pack, and the output end is connected to the second input end of the control circuit via the voltage following unit, the filtering unit and the voltage protection unit in sequence.

6. A portable energy storage system, comprising a portable energy storage device, characterized in that: further comprising at least one power pack device; The power pack device includes a battery pack, an online expansion module and a sampling control module; the battery pack is connected to a DC bus through the online expansion module, and the DC bus is connected to a bidirectional DC / AC converter of the portable energy storage device; The sampling control module includes a first voltage sampling circuit, a second voltage sampling circuit and a control circuit; the first voltage sampling circuit is used to detect the DC bus voltage, the second voltage sampling circuit is used to detect the battery pack voltage, and the control circuit is used to control the online expansion module to connect the battery pack online to the DC bus based on the DC bus voltage, the battery pack voltage and the parallel threshold; The online expansion module includes a first contactor, a second contactor and an anti-reverse diode, wherein the first end of the first contactor is connected to the positive electrode of the battery pack, and the second end is connected to the positive DC bus, the first end of the second contactor is connected to the positive electrode of the battery pack, and the second end is connected to the anode of the anti-reverse diode, the cathode of the anti-reverse diode is connected to the positive DC bus, and the negative electrode of the battery pack is connected to the negative DC bus; The control circuit is used to control the first contactor to close and the second contactor to open, or control the second contactor to close and the first contactor to open based on the DC bus voltage, the battery pack voltage and the parallel threshold.

7. The portable energy storage system according to claim 6, characterized in that: The sampling control module further includes a device incorporation judgment circuit, and the device incorporation judgment circuit is used to obtain the battery pack status; The control circuit is further configured to maintain current states of the first contactor and the second contactor based on the battery pack state, or control the first contactor and the second contactor to be disconnected.

8. The portable energy storage system according to claim 6, characterized in that: The first voltage sampling circuit includes a differential sampling unit, a voltage following unit, a filtering unit and a voltage protection unit. The input end of the differential sampling unit is connected to the positive DC bus and the negative DC bus, and the output end is connected to the first input end of the control circuit via the voltage following unit, the filtering unit and the voltage protection unit in sequence.

9. The portable energy storage system according to claim 6, characterized in that: The second voltage sampling circuit includes a differential sampling unit, a voltage following unit, a filtering unit and a voltage protection unit. The input end of the differential sampling unit is connected to the positive and negative poles of the battery pack, and the output end is connected to the second input end of the control circuit via the voltage following unit, the filtering unit and the voltage protection unit in sequence.

10. The portable energy storage system according to claim 6, characterized in that: It comprises a plurality of power-up pack devices, each of which is connected to the DC bus respectively.

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